-------- Original Message --------
Subject:        Re: USGS Topos - Blue Line Stream Designations
Date:   Thu, 31 May 2007 01:13:03 GMT
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Are you meaning double-line streams?  At the 1:100,000 scale it's
200 ft.

100000 * 0.008" * 3 (apparently the thinnest pen width) = 2400 inches
= 200 feet

So presumably a single-line stream is 66 ft.

As I recall, the calculations are similar for 1:24000 scale.

http://rockyweb.cr.usgs.gov/nmpstds/acrodocs/core3/2CR30197.PDF
The 1:100K standards are worded slightly differently -- you have to
order the hardcopy version.

http://rockyweb.cr.usgs.gov/nmpstds/omapstds.html

Joe McCollum
Forest Inventory and Analysis
Knoxville, TN  37919